Flow amplifying poppet valves commonly have a control chamber connected to an inlet port through an orifice and to the outlet port through a pilot passage. Opening of the poppet valve is controlled by controlling fluid flow through the pilot passage to create a pressure drop across the meter-in orifice to reduce the control pressure in the control chamber such that the inlet pressure urges the poppet off the valve seat when control pressure drops below the inlet pressure. The degree of opening of the popper is selectively controlled by regulating the flow through the pilot passage with a pilot valve.
One of the problems associated with the current popper valve designs is that because the degree of opening of the poppet fluctuates with changing flow forces acting on the poppet valve due to changing pressure conditions, there is no correlation between the degree of opening of the poppet and the degree of opening of the pilot valve.
Another problem is that the displacement of the poppet is dependant upon the volume of pilot flow through the pilot passage wherein increased opening of the poppet requires increased pilot flow. On larger poppet valves, the pilot flow becomes significant enough to impact on the pilot valve design. More particularly, if the pilot valve is controlled by a solenoid, a more powerful solenoid is required to move the pilot valve against the flow forces acting on the pilot valve.
The present invention is directed to overcoming one or more of the disadvantages or problems as set forth above.